This invention relates to a rotary cleaning brush device for cleaners of paved surfaces.
As is known, machines and equipment for cleaning floors and the like surfaces have long been available on the market. Such machines range from very simple designs to comparatively sophisticated designs for professional applications. In each case, they include devices having two or more cleaning brushes which are set for rotation close together to perform at least a substantial proportion of the cleaning operation.
Many cleaners have, for example, a brush head comprising two circular brushes mounted side-by-side for counter-rotation. The two brushes are close to each other but, of course, not tangent, and a sufficiently wide gap is left therebetween to avoid any interference and assembly problems.
The two brushes of such brush heads are aligned in a transverse direction but not in a perpendicular direction to the straight direction of advance of the heads, which would be coincident with the longitudinal centerline of such machines.
It has been found, in fact, that if the two brushes are aligned perpendicularly to the straight direction of advance, during the forward movement of the brush head in a straight line there is formed an unswept continuous thin stripe on a paved surface at the linear gap between the brushes.
In order to overcome this drawback, the two brushes are set obliquely to said longitudinal centerline. Thus, each brush is caused to act over an area which partly overlaps that of the other brush, thereby avoiding formation of an unswept stripe.
That arrangement has the disadvantage that it confers an irregular outline on the cleaner, increases the machine length dimension, and makes cleaning close against a wall, or in any case along the edges of floors, more difficult.
In fact, the cited brush head stands in many instances proud of such cleaners, on which it usually forms the foremost portion, and is to take an oblique attitude much like that of the brushes themselves. In this condition, it is the very forward working end of the machine which becomes asymmetrical relatively to the machine main extension.
These problems have led to the manufacture and sale of other cleaners provided with a brush head having three brushes, wherein two brushes are laid along a perpendicular direction to the machine longitudinal centerline and the third brush extends in an intermediate, either forward or rearward, set position, so as to form a triangular set of brushes.
It may be appreciated that the approach just described has good operational features, but involves a more complex and expensive construction than that using two brushes only and is significantly bulky. In general, this approach only becomes viable with cleaners of higher price and size.